The present invention relates to hydraulic shock absorbers for a motor vehicle suspension, and more particularly to a shock absorber constructed to become progressively stiffer during its service life.
In a conventional automotive suspension system, jounce and rebound movement is damped both by the friction in the system and by a hydraulic shock absorber. During repeated cycling of the suspension system, there will be a lessening of the friction in the various pivots and other components of the suspension due to wear and, consequently, a progressive reduction in friction damping. In order to compensate for changes in the friction damping characteristics of a vehicle suspension during its service life, it is an object of the present invention to provide a shock absorber that becomes progressively stiffer and increases its damping ability during its service life.